org.eclipse.ui.editors/src/org/eclipse/ui/internal/editors/text/SpellingConfigurationBlock.java - platform/eclipse.platform.text - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2008 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.editors.text;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.StackLayout;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Combo;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Shell;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.ISafeRunnable;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.core.runtime.Status;

 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ComboViewer;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredContentProvider;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.viewers.Viewer;

 import org.eclipse.ui.texteditor.spelling.IPreferenceStatusMonitor;
 import org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock;
 import org.eclipse.ui.texteditor.spelling.SpellingEngineDescriptor;
 import org.eclipse.ui.texteditor.spelling.SpellingService;

 import org.eclipse.ui.editors.text.EditorsUI;

 /**
  * Configures spelling preferences.
  *
  * @since 3.1
  */
 class SpellingConfigurationBlock implements IPreferenceConfigurationBlock {

 	/**
 	 * Error preferences block.
 	 */
 	private static class ErrorPreferences implements ISpellingPreferenceBlock {

 		/** Error message */
 		private String fMessage;

 		/** Error label */
 		private Label fLabel;

 		/**
 		 * Initialize with the given error message.
 		 *
 		 * @param message the error message
 		 */
 		protected ErrorPreferences(String message) {
 			fMessage= message;
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#createControl(org.eclipse.swt.widgets.Composite)
 		 */
 		public Control createControl(Composite composite) {
 			Composite inner= new Composite(composite, SWT.NONE);
 			inner.setLayout(new FillLayout(SWT.VERTICAL));

 			fLabel= new Label(inner, SWT.CENTER);
 			fLabel.setText(fMessage);

 			return inner;
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#initialize(org.eclipse.ui.texteditor.spelling.IStatusMonitor)
 		 */
 		public void initialize(IPreferenceStatusMonitor statusMonitor) {
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#canPerformOk()
 		 */
 		public boolean canPerformOk() {
 			return true;
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performOk()
 		 */
 		public void performOk() {
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performDefaults()
 		 */
 		public void performDefaults() {
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performRevert()
 		 */
 		public void performRevert() {
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#dispose()
 		 */
 		public void dispose() {
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#setEnabled(boolean)
 		 */
 		public void setEnabled(boolean enabled) {
 			fLabel.setEnabled(enabled);
 		}
 	}

 	/**
 	 * Forwarding status monitor for accessing the current status.
 	 */
 	private static class ForwardingStatusMonitor implements IPreferenceStatusMonitor {

 		/** Status monitor to which status changes are forwarded */
 		private IPreferenceStatusMonitor fForwardedMonitor;

 		/** Latest reported status */
 		private IStatus fStatus;

 		/**
 		 * Initializes with the given status monitor to which status changes are forwarded.
 		 *
 		 * @param forwardedMonitor the status monitor to which changes are forwarded
 		 */
 		public ForwardingStatusMonitor(IPreferenceStatusMonitor forwardedMonitor) {
 			fForwardedMonitor= forwardedMonitor;
 		}

 		/*
 		 * @see org.eclipse.ui.texteditor.spelling.IPreferenceStatusMonitor#statusChanged(org.eclipse.core.runtime.IStatus)
 		 */
 		public void statusChanged(IStatus status) {
 			fStatus= status;
 			fForwardedMonitor.statusChanged(status);
 		}

 		/**
 		 * Returns the latest reported status.
 		 *
 		 * @return the latest reported status, can be <code>null</code>
 		 */
 		public IStatus getStatus() {
 			return fStatus;
 		}
 	}

 	/** The overlay preference store. */
 	private final OverlayPreferenceStore fStore;

 	/* The controls */
 	private Combo fProviderCombo;
 	private Button fEnablementCheckbox;
 	private ComboViewer fProviderViewer;
 	private Composite fComboGroup;
 	private Composite fGroup;
 	private StackLayout fStackLayout;

 	/* the model */
 	private final Map fProviderDescriptors;
 	private final Map fProviderPreferences;
 	private final Map fProviderControls;

 	private ForwardingStatusMonitor fStatusMonitor;

 	private ISpellingPreferenceBlock fCurrentBlock;


 	public SpellingConfigurationBlock(OverlayPreferenceStore store, IPreferenceStatusMonitor statusMonitor) {
 		Assert.isNotNull(store);
 		fStore= store;
 		fStore.addKeys(createOverlayStoreKeys());
 		fStatusMonitor= new ForwardingStatusMonitor(statusMonitor);
 		fProviderDescriptors= createListModel();
 		fProviderPreferences= new HashMap();
 		fProviderControls= new HashMap();
 	}

 	private Map createListModel() {
 		SpellingEngineDescriptor[] descs= EditorsUI.getSpellingService().getSpellingEngineDescriptors();
 		Map map= new HashMap();
 		for (int i= 0; i < descs.length; i++) {
 			map.put(descs[i].getId(), descs[i]);
 		}
 		return map;
 	}

 	private OverlayPreferenceStore.OverlayKey[] createOverlayStoreKeys() {

 		ArrayList overlayKeys= new ArrayList();

 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, SpellingService.PREFERENCE_SPELLING_ENABLED));
 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING, SpellingService.PREFERENCE_SPELLING_ENGINE));

 		OverlayPreferenceStore.OverlayKey[] keys= new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
 		overlayKeys.toArray(keys);
 		return keys;
 	}

 	/**
 	 * Creates page for spelling preferences.
 	 *
 	 * @param parent the parent composite
 	 * @return the control for the preference page
 	 */
 	public Control createControl(Composite parent) {

 		Composite composite= new Composite(parent, SWT.NULL);
 		// assume parent page uses grid-data
 		GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_CENTER | GridData.VERTICAL_ALIGN_FILL);
 		composite.setLayoutData(gd);
 		GridLayout layout= new GridLayout();
 		layout.numColumns= 2;
 		layout.marginHeight= 0;
 		layout.marginWidth= 0;

 		PixelConverter pc= new PixelConverter(composite);
 		layout.verticalSpacing= pc.convertHeightInCharsToPixels(1) / 2;
 		composite.setLayout(layout);

 		if (EditorsUI.getSpellingService().getSpellingEngineDescriptors().length == 0) {
 			Label label= new Label(composite, SWT.NONE);
 			label.setText(TextEditorMessages.SpellingConfigurationBlock_error_not_installed);
 			return composite;
 		}

 		/* check box for new editors */
 		fEnablementCheckbox= new Button(composite, SWT.CHECK);
 		fEnablementCheckbox.setText(TextEditorMessages.SpellingConfigurationBlock_enable);
 		gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING);
 		fEnablementCheckbox.setLayoutData(gd);
 		fEnablementCheckbox.addSelectionListener(new SelectionListener() {
 			public void widgetSelected(SelectionEvent e) {
 				boolean enabled= fEnablementCheckbox.getSelection();
 				fStore.setValue(SpellingService.PREFERENCE_SPELLING_ENABLED, enabled);
 				updateCheckboxDependencies();
 			}

 			public void widgetDefaultSelected(SelectionEvent e) {
 			}
 		});

 		Label label= new Label(composite, SWT.CENTER);
 		gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 		label.setLayoutData(gd);

 		if (fProviderDescriptors.size() > 1) {
 			fComboGroup= new Composite(composite, SWT.NONE);
 			gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 			gd.horizontalIndent= 10;
 			fComboGroup.setLayoutData(gd);
 			GridLayout gridLayout= new GridLayout(2, false);
 			gridLayout.marginWidth= 0;
 			fComboGroup.setLayout(gridLayout);

 			Label comboLabel= new Label(fComboGroup, SWT.CENTER);
 			gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_CENTER);
 			comboLabel.setLayoutData(gd);
 			comboLabel.setText(TextEditorMessages.SpellingConfigurationBlock_combo_caption);

 			label= new Label(composite, SWT.CENTER);
 			gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 			label.setLayoutData(gd);

 			fProviderCombo= new Combo(fComboGroup, SWT.READ_ONLY | SWT.DROP_DOWN);
 			gd= new GridData(GridData.HORIZONTAL_ALIGN_END | GridData.VERTICAL_ALIGN_CENTER);
 			fProviderCombo.setLayoutData(gd);

 			fProviderViewer= createProviderViewer();
 		}

 		Composite groupComp= new Composite(composite, SWT.NONE);
 		gd= new GridData(GridData.FILL_BOTH);
 		gd.horizontalSpan= 2;
 		groupComp.setLayoutData(gd);
 		GridLayout gridLayout= new GridLayout(1, false);
 		gridLayout.marginWidth= 0;
 		groupComp.setLayout(gridLayout);

 		/* contributed provider preferences. */
 		fGroup= new Composite(groupComp, SWT.NONE);
 		gd= new GridData(SWT.FILL, SWT.FILL, true, true);
 		gd.horizontalIndent= 10;
 		fGroup.setLayoutData(gd);
 		fStackLayout= new StackLayout();
 		fGroup.setLayout(fStackLayout);

 		return composite;
 	}

 	/*
 	 * @see org.eclipse.ui.internal.editors.text.IPreferenceConfigurationBlock#applyData(java.lang.Object)
 	 * @since 3.4
 	 */
 	public void applyData(Object data) {
 	}

 	private ComboViewer createProviderViewer() {
 		/* list viewer */
 		final ComboViewer viewer= new ComboViewer(fProviderCombo);
 		viewer.setContentProvider(new IStructuredContentProvider() {

 			/*
 			 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
 			 */
 			public void dispose() {
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
 			 */
 			public void inputChanged(Viewer v, Object oldInput, Object newInput) {
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
 			 */
 			public Object[] getElements(Object inputElement) {
 				return fProviderDescriptors.values().toArray();
 			}
 		});
 		viewer.setLabelProvider(new LabelProvider() {
 			/*
 			 * @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
 			 */
 			public Image getImage(Object element) {
 				return null;
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
 			 */
 			public String getText(Object element) {
 				return ((SpellingEngineDescriptor) element).getLabel();
 			}
 		});
 		viewer.addSelectionChangedListener(new ISelectionChangedListener() {

 			public void selectionChanged(SelectionChangedEvent event) {
 				IStructuredSelection sel= (IStructuredSelection) event.getSelection();
 				if (sel.isEmpty())
 					return;
 				if (fCurrentBlock != null && fStatusMonitor.getStatus() != null && fStatusMonitor.getStatus().matches(IStatus.ERROR))
 					if (isPerformRevert()) {
 						ISafeRunnable runnable= new ISafeRunnable() {
 							public void run() throws Exception {
 								fCurrentBlock.performRevert();
 							}
 							public void handleException(Throwable x) {
 							}
 						};
 						SafeRunner.run(runnable);
 					} else {
 						revertSelection();
 						return;
 					}
 				fStore.setValue(SpellingService.PREFERENCE_SPELLING_ENGINE, ((SpellingEngineDescriptor) sel.getFirstElement()).getId());
 				updateListDependencies();
 			}

 			private boolean isPerformRevert() {
 				Shell shell= viewer.getControl().getShell();
 				MessageDialog dialog= new MessageDialog(shell, TextEditorMessages.SpellingConfigurationBlock_error_title, null, TextEditorMessages.SpellingConfigurationBlock_error_message, MessageDialog.QUESTION, new String[] { IDialogConstants.YES_LABEL, IDialogConstants.NO_LABEL }, 1);
 				return dialog.open() == 0;
 			}

 			private void revertSelection() {
 				try {
 					viewer.removeSelectionChangedListener(this);
 					SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
 					if (desc != null)
 						viewer.setSelection(new StructuredSelection(desc), true);
 				} finally {
 					viewer.addSelectionChangedListener(this);
 				}
 			}
 		});
 		viewer.setInput(fProviderDescriptors);
 		viewer.refresh();

 		return viewer;
 	}

 	private void updateCheckboxDependencies() {
 		final boolean enabled= fEnablementCheckbox.getSelection();
 		if (fComboGroup != null)
 			setEnabled(fComboGroup, enabled);
 		SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
 		String id= desc != null ? desc.getId() : ""; //$NON-NLS-1$
 		final ISpellingPreferenceBlock preferenceBlock= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
 		if (preferenceBlock != null) {
 			ISafeRunnable runnable= new ISafeRunnable() {
 				public void run() throws Exception {
 					preferenceBlock.setEnabled(enabled);
 				}
 				public void handleException(Throwable x) {
 				}
 			};
 			SafeRunner.run(runnable);
 		}
 	}

 	private void setEnabled(Control control, boolean enabled) {
 		if (control instanceof Composite) {
 			Control[] children= ((Composite) control).getChildren();
 			for (int i= 0; i < children.length; i++)
 				setEnabled(children[i], enabled);
 		}
 		control.setEnabled(enabled);
 	}

 	void updateListDependencies() {
 		SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
 		String id;
 		if (desc == null) {
 			// safety in case there is no such descriptor
 			id= ""; //$NON-NLS-1$
 			String message= TextEditorMessages.SpellingConfigurationBlock_error_not_exist;
 			EditorsPlugin.log(new Status(IStatus.WARNING, EditorsUI.PLUGIN_ID, IStatus.OK, message, null));
 			fCurrentBlock= new ErrorPreferences(message);
 		} else {
 			id= desc.getId();
 			fCurrentBlock= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
 			if (fCurrentBlock == null) {
 				try {
 					fCurrentBlock= desc.createPreferences();
 					fProviderPreferences.put(id, fCurrentBlock);
 				} catch (CoreException e) {
 					EditorsPlugin.log(e);
 					fCurrentBlock= new ErrorPreferences(e.getLocalizedMessage());
 				}
 			}
 		}

 		Control control= (Control) fProviderControls.get(id);
 		if (control == null) {
 			final Control[] result= new Control[1];
 			ISafeRunnable runnable= new ISafeRunnable() {
 				public void run() throws Exception {
 					result[0]= fCurrentBlock.createControl(fGroup);
 				}
 				public void handleException(Throwable x) {
 				}
 			};
 			SafeRunner.run(runnable);
 			control= result[0];
 			if (control == null) {
 				String message= TextEditorMessages.SpellingConfigurationBlock_info_no_preferences;
 				EditorsPlugin.log(new Status(IStatus.WARNING, EditorsUI.PLUGIN_ID, IStatus.OK, message, null));
 				control= new ErrorPreferences(message).createControl(fGroup);
 			} else {
 				fProviderControls.put(id, control);
 			}
 		}
 		Dialog.applyDialogFont(control);
 		fStackLayout.topControl= control;
 		control.pack();
 		fGroup.layout();
 		fGroup.getParent().layout();

 		fStatusMonitor.statusChanged(new StatusInfo());
 		ISafeRunnable runnable= new ISafeRunnable() {
 			public void run() throws Exception {
 				fCurrentBlock.initialize(fStatusMonitor);
 			}
 			public void handleException(Throwable x) {
 			}
 		};
 		SafeRunner.run(runnable);
 	}

 	public void initialize() {
 		restoreFromPreferences();
 	}

 	public boolean canPerformOk() {
 		SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
 		String id= desc != null ? desc.getId() : ""; //$NON-NLS-1$
 		final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
 		if (block == null)
 			return true;

 		final Boolean[] result= new Boolean[] { Boolean.TRUE };
 		ISafeRunnable runnable= new ISafeRunnable() {
 			public void run() throws Exception {
 				result[0]= Boolean.valueOf(block.canPerformOk());
 			}
 			public void handleException(Throwable x) {
 			}
 		};
 		SafeRunner.run(runnable);
 		return result[0].booleanValue();
 	}

 	public void performOk() {
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
 			ISafeRunnable runnable= new ISafeRunnable() {
 				public void run() throws Exception {
 					block.performOk();
 				}
 				public void handleException(Throwable x) {
 				}
 			};
 			SafeRunner.run(runnable);
 		}
 	}

 	public void performDefaults() {
 		restoreFromPreferences();
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
 			ISafeRunnable runnable= new ISafeRunnable() {
 				public void run() throws Exception {
 					block.performDefaults();
 				}
 				public void handleException(Throwable x) {
 				}
 			};
 			SafeRunner.run(runnable);
 		}
 	}

 	public void dispose() {
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
 			ISafeRunnable runnable= new ISafeRunnable() {
 				public void run() throws Exception {
 					block.dispose();
 				}
 				public void handleException(Throwable x) {
 				}
 			};
 			SafeRunner.run(runnable);
 		}
 	}

 	private void restoreFromPreferences() {
 		if (fEnablementCheckbox == null)
 			return;

 		boolean enabled= fStore.getBoolean(SpellingService.PREFERENCE_SPELLING_ENABLED);
 		fEnablementCheckbox.setSelection(enabled);

 		if (fProviderViewer == null)
 			updateListDependencies();
 		else {
 			SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
 			if (desc != null)
 				fProviderViewer.setSelection(new StructuredSelection(desc), true);
 		}

 		updateCheckboxDependencies();
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2008 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.ui.internal.editors.text;

	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Map;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.StackLayout;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.layout.FillLayout;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Combo;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Shell;

	import org.eclipse.core.runtime.Assert;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.ISafeRunnable;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.SafeRunner;
	import org.eclipse.core.runtime.Status;

	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.MessageDialog;
	import org.eclipse.jface.viewers.ComboViewer;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredContentProvider;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.LabelProvider;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.jface.viewers.Viewer;

	import org.eclipse.ui.texteditor.spelling.IPreferenceStatusMonitor;
	import org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock;
	import org.eclipse.ui.texteditor.spelling.SpellingEngineDescriptor;
	import org.eclipse.ui.texteditor.spelling.SpellingService;

	import org.eclipse.ui.editors.text.EditorsUI;

	/**
	* Configures spelling preferences.
	*
	* @since 3.1
	*/
	class SpellingConfigurationBlock implements IPreferenceConfigurationBlock {

	/**
	* Error preferences block.
	*/
	private static class ErrorPreferences implements ISpellingPreferenceBlock {

	/** Error message */
	private String fMessage;

	/** Error label */
	private Label fLabel;

	/**
	* Initialize with the given error message.
	*
	* @param message the error message
	*/
	protected ErrorPreferences(String message) {
	fMessage= message;
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#createControl(org.eclipse.swt.widgets.Composite)
	*/
	public Control createControl(Composite composite) {
	Composite inner= new Composite(composite, SWT.NONE);
	inner.setLayout(new FillLayout(SWT.VERTICAL));

	fLabel= new Label(inner, SWT.CENTER);
	fLabel.setText(fMessage);

	return inner;
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#initialize(org.eclipse.ui.texteditor.spelling.IStatusMonitor)
	*/
	public void initialize(IPreferenceStatusMonitor statusMonitor) {
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#canPerformOk()
	*/
	public boolean canPerformOk() {
	return true;
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performOk()
	*/
	public void performOk() {
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performDefaults()
	*/
	public void performDefaults() {
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#performRevert()
	*/
	public void performRevert() {
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#dispose()
	*/
	public void dispose() {
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.ISpellingPreferenceBlock#setEnabled(boolean)
	*/
	public void setEnabled(boolean enabled) {
	fLabel.setEnabled(enabled);
	}
	}

	/**
	* Forwarding status monitor for accessing the current status.
	*/
	private static class ForwardingStatusMonitor implements IPreferenceStatusMonitor {

	/** Status monitor to which status changes are forwarded */
	private IPreferenceStatusMonitor fForwardedMonitor;

	/** Latest reported status */
	private IStatus fStatus;

	/**
	* Initializes with the given status monitor to which status changes are forwarded.
	*
	* @param forwardedMonitor the status monitor to which changes are forwarded
	*/
	public ForwardingStatusMonitor(IPreferenceStatusMonitor forwardedMonitor) {
	fForwardedMonitor= forwardedMonitor;
	}

	/*
	* @see org.eclipse.ui.texteditor.spelling.IPreferenceStatusMonitor#statusChanged(org.eclipse.core.runtime.IStatus)
	*/
	public void statusChanged(IStatus status) {
	fStatus= status;
	fForwardedMonitor.statusChanged(status);
	}

	/**
	* Returns the latest reported status.
	*
	* @return the latest reported status, can be <code>null</code>
	*/
	public IStatus getStatus() {
	return fStatus;
	}
	}

	/** The overlay preference store. */
	private final OverlayPreferenceStore fStore;

	/* The controls */
	private Combo fProviderCombo;
	private Button fEnablementCheckbox;
	private ComboViewer fProviderViewer;
	private Composite fComboGroup;
	private Composite fGroup;
	private StackLayout fStackLayout;

	/* the model */
	private final Map fProviderDescriptors;
	private final Map fProviderPreferences;
	private final Map fProviderControls;

	private ForwardingStatusMonitor fStatusMonitor;

	private ISpellingPreferenceBlock fCurrentBlock;


	public SpellingConfigurationBlock(OverlayPreferenceStore store, IPreferenceStatusMonitor statusMonitor) {
	Assert.isNotNull(store);
	fStore= store;
	fStore.addKeys(createOverlayStoreKeys());
	fStatusMonitor= new ForwardingStatusMonitor(statusMonitor);
	fProviderDescriptors= createListModel();
	fProviderPreferences= new HashMap();
	fProviderControls= new HashMap();
	}

	private Map createListModel() {
	SpellingEngineDescriptor[] descs= EditorsUI.getSpellingService().getSpellingEngineDescriptors();
	Map map= new HashMap();
	for (int i= 0; i < descs.length; i++) {
	map.put(descs[i].getId(), descs[i]);
	}
	return map;
	}

	private OverlayPreferenceStore.OverlayKey[] createOverlayStoreKeys() {

	ArrayList overlayKeys= new ArrayList();

	overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, SpellingService.PREFERENCE_SPELLING_ENABLED));
	overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING, SpellingService.PREFERENCE_SPELLING_ENGINE));

	OverlayPreferenceStore.OverlayKey[] keys= new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
	overlayKeys.toArray(keys);
	return keys;
	}

	/**
	* Creates page for spelling preferences.
	*
	* @param parent the parent composite
	* @return the control for the preference page
	*/
	public Control createControl(Composite parent) {

	Composite composite= new Composite(parent, SWT.NULL);
	// assume parent page uses grid-data
	GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_CENTER \| GridData.VERTICAL_ALIGN_FILL);
	composite.setLayoutData(gd);
	GridLayout layout= new GridLayout();
	layout.numColumns= 2;
	layout.marginHeight= 0;
	layout.marginWidth= 0;

	PixelConverter pc= new PixelConverter(composite);
	layout.verticalSpacing= pc.convertHeightInCharsToPixels(1) / 2;
	composite.setLayout(layout);

	if (EditorsUI.getSpellingService().getSpellingEngineDescriptors().length == 0) {
	Label label= new Label(composite, SWT.NONE);
	label.setText(TextEditorMessages.SpellingConfigurationBlock_error_not_installed);
	return composite;
	}

	/* check box for new editors */
	fEnablementCheckbox= new Button(composite, SWT.CHECK);
	fEnablementCheckbox.setText(TextEditorMessages.SpellingConfigurationBlock_enable);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING \| GridData.VERTICAL_ALIGN_BEGINNING);
	fEnablementCheckbox.setLayoutData(gd);
	fEnablementCheckbox.addSelectionListener(new SelectionListener() {
	public void widgetSelected(SelectionEvent e) {
	boolean enabled= fEnablementCheckbox.getSelection();
	fStore.setValue(SpellingService.PREFERENCE_SPELLING_ENABLED, enabled);
	updateCheckboxDependencies();
	}

	public void widgetDefaultSelected(SelectionEvent e) {
	}
	});

	Label label= new Label(composite, SWT.CENTER);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	label.setLayoutData(gd);

	if (fProviderDescriptors.size() > 1) {
	fComboGroup= new Composite(composite, SWT.NONE);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	gd.horizontalIndent= 10;
	fComboGroup.setLayoutData(gd);
	GridLayout gridLayout= new GridLayout(2, false);
	gridLayout.marginWidth= 0;
	fComboGroup.setLayout(gridLayout);

	Label comboLabel= new Label(fComboGroup, SWT.CENTER);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING \| GridData.VERTICAL_ALIGN_CENTER);
	comboLabel.setLayoutData(gd);
	comboLabel.setText(TextEditorMessages.SpellingConfigurationBlock_combo_caption);

	label= new Label(composite, SWT.CENTER);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	label.setLayoutData(gd);

	fProviderCombo= new Combo(fComboGroup, SWT.READ_ONLY \| SWT.DROP_DOWN);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_END \| GridData.VERTICAL_ALIGN_CENTER);
	fProviderCombo.setLayoutData(gd);

	fProviderViewer= createProviderViewer();
	}

	Composite groupComp= new Composite(composite, SWT.NONE);
	gd= new GridData(GridData.FILL_BOTH);
	gd.horizontalSpan= 2;
	groupComp.setLayoutData(gd);
	GridLayout gridLayout= new GridLayout(1, false);
	gridLayout.marginWidth= 0;
	groupComp.setLayout(gridLayout);

	/* contributed provider preferences. */
	fGroup= new Composite(groupComp, SWT.NONE);
	gd= new GridData(SWT.FILL, SWT.FILL, true, true);
	gd.horizontalIndent= 10;
	fGroup.setLayoutData(gd);
	fStackLayout= new StackLayout();
	fGroup.setLayout(fStackLayout);

	return composite;
	}

	/*
	* @see org.eclipse.ui.internal.editors.text.IPreferenceConfigurationBlock#applyData(java.lang.Object)
	* @since 3.4
	*/
	public void applyData(Object data) {
	}

	private ComboViewer createProviderViewer() {
	/* list viewer */
	final ComboViewer viewer= new ComboViewer(fProviderCombo);
	viewer.setContentProvider(new IStructuredContentProvider() {

	/*
	* @see org.eclipse.jface.viewers.IContentProvider#dispose()
	*/
	public void dispose() {
	}

	/*
	* @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
	*/
	public void inputChanged(Viewer v, Object oldInput, Object newInput) {
	}

	/*
	* @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
	*/
	public Object[] getElements(Object inputElement) {
	return fProviderDescriptors.values().toArray();
	}
	});
	viewer.setLabelProvider(new LabelProvider() {
	/*
	* @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
	*/
	public Image getImage(Object element) {
	return null;
	}

	/*
	* @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
	*/
	public String getText(Object element) {
	return ((SpellingEngineDescriptor) element).getLabel();
	}
	});
	viewer.addSelectionChangedListener(new ISelectionChangedListener() {

	public void selectionChanged(SelectionChangedEvent event) {
	IStructuredSelection sel= (IStructuredSelection) event.getSelection();
	if (sel.isEmpty())
	return;
	if (fCurrentBlock != null && fStatusMonitor.getStatus() != null && fStatusMonitor.getStatus().matches(IStatus.ERROR))
	if (isPerformRevert()) {
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	fCurrentBlock.performRevert();
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	} else {
	revertSelection();
	return;
	}
	fStore.setValue(SpellingService.PREFERENCE_SPELLING_ENGINE, ((SpellingEngineDescriptor) sel.getFirstElement()).getId());
	updateListDependencies();
	}

	private boolean isPerformRevert() {
	Shell shell= viewer.getControl().getShell();
	MessageDialog dialog= new MessageDialog(shell, TextEditorMessages.SpellingConfigurationBlock_error_title, null, TextEditorMessages.SpellingConfigurationBlock_error_message, MessageDialog.QUESTION, new String[] { IDialogConstants.YES_LABEL, IDialogConstants.NO_LABEL }, 1);
	return dialog.open() == 0;
	}

	private void revertSelection() {
	try {
	viewer.removeSelectionChangedListener(this);
	SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
	if (desc != null)
	viewer.setSelection(new StructuredSelection(desc), true);
	} finally {
	viewer.addSelectionChangedListener(this);
	}
	}
	});
	viewer.setInput(fProviderDescriptors);
	viewer.refresh();

	return viewer;
	}

	private void updateCheckboxDependencies() {
	final boolean enabled= fEnablementCheckbox.getSelection();
	if (fComboGroup != null)
	setEnabled(fComboGroup, enabled);
	SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
	String id= desc != null ? desc.getId() : ""; //$NON-NLS-1$
	final ISpellingPreferenceBlock preferenceBlock= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
	if (preferenceBlock != null) {
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	preferenceBlock.setEnabled(enabled);
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	}
	}

	private void setEnabled(Control control, boolean enabled) {
	if (control instanceof Composite) {
	Control[] children= ((Composite) control).getChildren();
	for (int i= 0; i < children.length; i++)
	setEnabled(children[i], enabled);
	}
	control.setEnabled(enabled);
	}

	void updateListDependencies() {
	SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
	String id;
	if (desc == null) {
	// safety in case there is no such descriptor
	id= ""; //$NON-NLS-1$
	String message= TextEditorMessages.SpellingConfigurationBlock_error_not_exist;
	EditorsPlugin.log(new Status(IStatus.WARNING, EditorsUI.PLUGIN_ID, IStatus.OK, message, null));
	fCurrentBlock= new ErrorPreferences(message);
	} else {
	id= desc.getId();
	fCurrentBlock= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
	if (fCurrentBlock == null) {
	try {
	fCurrentBlock= desc.createPreferences();
	fProviderPreferences.put(id, fCurrentBlock);
	} catch (CoreException e) {
	EditorsPlugin.log(e);
	fCurrentBlock= new ErrorPreferences(e.getLocalizedMessage());
	}
	}
	}

	Control control= (Control) fProviderControls.get(id);
	if (control == null) {
	final Control[] result= new Control[1];
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	result[0]= fCurrentBlock.createControl(fGroup);
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	control= result[0];
	if (control == null) {
	String message= TextEditorMessages.SpellingConfigurationBlock_info_no_preferences;
	EditorsPlugin.log(new Status(IStatus.WARNING, EditorsUI.PLUGIN_ID, IStatus.OK, message, null));
	control= new ErrorPreferences(message).createControl(fGroup);
	} else {
	fProviderControls.put(id, control);
	}
	}
	Dialog.applyDialogFont(control);
	fStackLayout.topControl= control;
	control.pack();
	fGroup.layout();
	fGroup.getParent().layout();

	fStatusMonitor.statusChanged(new StatusInfo());
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	fCurrentBlock.initialize(fStatusMonitor);
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	}

	public void initialize() {
	restoreFromPreferences();
	}

	public boolean canPerformOk() {
	SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
	String id= desc != null ? desc.getId() : ""; //$NON-NLS-1$
	final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) fProviderPreferences.get(id);
	if (block == null)
	return true;

	final Boolean[] result= new Boolean[] { Boolean.TRUE };
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	result[0]= Boolean.valueOf(block.canPerformOk());
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	return result[0].booleanValue();
	}

	public void performOk() {
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	block.performOk();
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	}
	}

	public void performDefaults() {
	restoreFromPreferences();
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	block.performDefaults();
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	}
	}

	public void dispose() {
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	final ISpellingPreferenceBlock block= (ISpellingPreferenceBlock) it.next();
	ISafeRunnable runnable= new ISafeRunnable() {
	public void run() throws Exception {
	block.dispose();
	}
	public void handleException(Throwable x) {
	}
	};
	SafeRunner.run(runnable);
	}
	}

	private void restoreFromPreferences() {
	if (fEnablementCheckbox == null)
	return;

	boolean enabled= fStore.getBoolean(SpellingService.PREFERENCE_SPELLING_ENABLED);
	fEnablementCheckbox.setSelection(enabled);

	if (fProviderViewer == null)
	updateListDependencies();
	else {
	SpellingEngineDescriptor desc= EditorsUI.getSpellingService().getActiveSpellingEngineDescriptor(fStore);
	if (desc != null)
	fProviderViewer.setSelection(new StructuredSelection(desc), true);
	}

	updateCheckboxDependencies();
	}
	}